This project will examine the impact of two different forms of meditation training on aspects of emotion regulation. One form of meditation is specifically designed to prime and enhance qualities of compassion and loving kindness. Another form of meditation-mindfulness meditation-is said to alter an individual's relationship with his/her emotions so that the individual is less identified with them and they are less likely to perseverate. A major goal of this project is to investigate the impact of these forms of mental training on emotional reactivity and regulation. This goal will be realized by the investigation of two primary samples: 1. Individuals undergoing a standardized program of 8 weeks of mindfulness-based stress reduction (MBSR) that includes training in loving-kindness and compassion;and 2. individuals who are expert meditators with daily meditation practices of at least 30 minutes/day for 10 years that include both lovingkindness/ compassion and mindfulness meditation. Among this latter group of participants, we will conduct assessments on three occasions: an initial testing session without preceding meditation;after an intensive day of 10 hours of practice of compassion/loving-kindness meditation;and after an intensive day of 10 hours of practice of mindfulness meditation. Assessment of the MBSR group will be longitudinal since we can obtain assessments before and after the training is presented. A four-month follow-up period will also be included for the MBSR group. We will also use a highly structured, very well-matched comparison group for the MBSR group, one that we have termed the Health Enhancement Program (HEP) that is matched on hours of contact, daily practice, class structure etc., but that does not include a mindfulness or lovingkindness/compassion component. Participants from each of these samples will be tested in laboratorysessions conducted over the course of two days to assess the impact of loving-kindness/compassion meditation and mindfulness meditation on reactivity to and recovery from emotional pictures that depict human suffering. Peripheral physiological reactivity and recovery will be measured with startle and facial electromyography and the neural circuitry associated with reactivity and recovery will be assessed with functional magnetic resonance imaging (fMRI). We will also investigate the impact of these different forms of meditation on cortisol reactivity to the Trier Social Stress Task (TSST) and examine relations between changes in the brain produced by the meditation practices and changes in response to the TSST. Finally, relations between measures obtained in this project and in Projects 2 and 3 will also be assessed.